Anthelmintic treatment strategies: current status and future.
Despite the array of anthelmintics and endectocides and delivery systems available for use in the prevention and control of nematode parasites of ruminants, the number of highly effective control programs that have been developed and even the number of such programs that have been successfully implemented in commercial animal production, there have been no recent innovations or discoveries in regard to strategies, new anthelmintics, or systems for controlling nematode parasites through anthelmintic use. In the traditional sense of chemotherapy-chemoprophylaxis, we have probably achieved the maximum effect of what is possible from excellent anthelmintics developed by the pharmaceutical industry over the last 35 years, i.e. from thiabendazole through levamisole and morantel tartrate, to more advanced benzimidazoles and to the avermectins and milbemycins. At the core of all anthelmintic treatment-related problems is the lingering conception among a large body of animal producers that anthelmintic treatment is the only effort needed to control parasitism and its effects on host animals. This concept has given rise to the long-standing difficulty of drug resistance in sheep nematodes and the not remote possibility of its development in nematodes of cattle. Along with this are serious concerns over environmental toxicity, tissue residues and enormous financial investment to develop new and novel anthelmintic compounds. Progress is being made in current and intensive searches for development and testing of control approaches alternative to anthelmintics, e.g. helminth vaccines, biological control agents such as fungi, selection of resistant sires, alternative chemicals and nematode growth regulators. A timetable for when alternative controls can be developed fully and put into practical use cannot be predicted. It is universally acknowledged among parasitologists that existing anthelmintics must be preserved and utilized judiciously to ensure continued effectiveness. A major example is to be found in strategic or integrated control programs in Australia developed over the last 10 years to combat widespread drug resistance in sheep. Major imperatives for future programs and systems of controlling nematode parasites of ruminants are improved means of getting producers to adopt proven and sustainable methods.
Williams
J C
JC
Department of Veterinary Science, Louisiana Agricultural Experiment Station, LSU Agricultural Center, Baton Rouge 70803-6002, USA.
D000822:Animal Husbandry / Q000592:standards; D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases; D002980:Climate; D003140:Communicable Disease Control / Q000379:methods; D009349:Nematode Infections / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary*; D012418:Ruminants; D012756:Sheep; D012757:Sheep Diseases
D000871:Anthelmintics